The AST editor golem is really cool. But the habit of wanting to move around and delete single text characters can be trained out of you, just like people who use vim.
Right, and I'm saying that a huge amount of users wouldn't pass that initial barrier of training before dropping it. Vim's ubiquity, general applicability and community helped it achieve popularity; I do think it succeeded despite having less stellar error prompts as I described above. Current AST editors are frequently domain/language-specific and don't have the advantage of e.g. general applicability, so they need much better error prompts and other hand-holding stuff to make up for it.
Right, and I'm saying that a huge amount of users wouldn't pass that initial barrier of training before dropping it.
This may be the case. But these people (myself included!) are getting older by the day, and will eventually die or move into management roles. The students in the audience of the talk may well end up working at Facebook using AST editors, and in 10 years that will simply be the new normal.